超高心墙堆石坝长期运行应力变形研究

鉴于超高心墙堆石坝的长期变形规律对其正常运行维护具有重要意义,基于广义塑性模型,综合考虑坝料流变和湿化特性,采用三维固结有限元法对300m级超高心墙堆石坝进行变形和应力分析,分别讨论了循环水荷载、坝料流变及湿化特性对大坝长期变形的影响。结果表明,三维固结有限元计算得到的坝体变形满足安全要求,符合土石坝变形基本规律;统一广义塑性模型可反映坝体心墙在循环加、卸载作用下的塑性变形累积现象,流变对超高心墙堆石坝的长期变形有重要影响;大坝长期运行过程中,上游坝壳的湿化特性所引起的大幅湿陷变形是后期沉降的主要原因,同时会导致坝体向上游倾斜;竣工期大坝心墙内存在一定的孔隙水压力,水库蓄水运行后,随着大坝变形趋于稳定,坝体应力分布亦趋于稳定状态。

Research of Stress and Deformation Characteristics of Super-high Core Rock-fill Dam in Long-term Running Conditions

Given the long-term deformation law of super-high core rock-fill dam is of great significance to its normal operation,based on the generalized plasticity model,the stress and deformation behavior of a 300 msuper-high core rockfill dam was analyzed by use of the three-dimensional consolidation finite element program.In addition,the influence of circulating water load,rheological properties and wetting characteristics of the dam materials on the final deformation of the dam in long-term conditions was discussed separately.The results show that the deformation of the dam obtained by three-dimensional consolidation finite element calculation meets the safety requirements and conforms to the basic law of deformation of earth-rock dam.The generalized plasticity theory is capable of modelling the cumulative deformation of the rock-fill materials under cyclic load and unload,and the rheology has an important influence on the long-term deformation of the high core wall rock-fill dam.The large collapsible deformation caused by the wetting characteristics of the upstream dam shell is significant in the final settlement of the dam,which also makes the dam’s body inclined to the upstream.There remained a certain pore water pressure in the core wall of the dam when the dam was just completed.The deformation of the dam tends to be steady after reservoir storage operation,the stress distributions of the dam also becomes stable.